• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.03a
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• pp.93-100
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• 2003

Seismic isolation systems can improve the seismic safety of nuclear power plants by decreasing seismic force transmitted to structures and equipment. This study evaluates the effectiveness of equipment seismic isolation systems by the comparison of core damage frequencies in non-isolated and isolated cases. It can be found that the seismic isolation systems increase seismic capacity of nuclear equipment and decrease core damage frequencies significantly. The effect of equipment isolation is more significant in the PGA range of 0.3g to 0.5g.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.09a
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• pp.403-410
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• 2003

This paper presents the results of experimental studies on the equipment isolation effect in the nuclear containment. For this purpose, shaking table tests were performed. The isolation system, known as Friction Pendulum System (FPS), combines the concepts of sliding bearings and pendulum motion was selected. Peak ground acceleration, bidirectional motion, effect of vertical motion and frequency contents of selected earthquake motions were considered. Finally, it is presented that the FPS systems are effective for the small equipment isolation. Key word equipment isolation, nuclear containment, shaking table test, Friction Pendulum System (FPS)

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.09a
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• pp.411-418
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• 2003

This paper presents the results of experimental studies on the equipment isolation effect in the nuclear containment. for this Purpose, shaking table tests were performed. The natural rubber bearing (NRB) and high damping rubber bearing (HDRB) were selected for the isolation. Peak ground acceleration, damping characteristics of isolation system and frequency contents of selected earthquake motions were considered. finally, it is presented that the NRB and HDRB systems are effective for the small equipment isolation and the damping of isolation systems can be affected to the seismic isolation effect.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2005.03a
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• pp.497-504
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• 2005

This paper presents the results of experimental studies on the equipment isolation effect considering the floor response. For this purpose, shaking table tests were performed. For the measuring the floor response, numerical analysis was performed. For the isolation for the equipment, Natural Rubber Bearing(NRB), High Damping Rubber Bearing(HDRB) and Friction Pendulum System(FPS) were used. Finally, it is presented that the isolation systems used in this test can be adopted for the small equipment isolation. But the rubber bearing used in this study affected to the temperature change very sensitively.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.10a
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• pp.472-472
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• 2009

The safety of cultural properties, medical treatment and electrical communication equipments in a building was hardly considered against the earthquake induced vibration, while the integrity of the building structure has been taken into account through the resistant earthquake design. This paper presents design of a seismic isolation table for both indoor and outdoor electrical communication equipment. First of all, artificial earthquake waves compatible with floor and ground response spectra for electrical communication equipments are generated using previously recorded seismic waves. Two kinds of one-degree-of-freedom seismic isolation table systems: spring-linear damper and spring-friction damper systems are considered and their responses to artificial earthquake waves are simulated. Design parameter study for two seismic isolation tables are performed through simulations and a seismic isolation table for both indoor and outdoor electrical communication equipment is designed considering the simulation results.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.10a
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• pp.227-232
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• 2003

As the most precision equipment requiring very strict vibration environment are vulnerable to the surrounding vibration condition, they adapt the passive or active vibration isolation system. When it comes to the passive isolation system, the resonance of the isolation system causes excessive resonance response, and finally results in the degrade the equipment performance. This paper deals with the active control method to control this resonance induced response, and includes the experiment on the active control for controlling the resonance response on the table against the excitation of the same frequency with the natural frequency of the isolation system. The electromagnetic actuator was designed and the control effect was verified by the experiment. The experiment showed that the electromagnetic actuator is effective for controlling the low frequency isolation resonance response of the precision equipment.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.10a
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• pp.185-189
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• 2009

It is very important to control the vibration transmitted from external utilities and the transient response due to the internal sources for the precision equipment, which is very sensitive to the vibration environment. The anti-vibration tables that use air springs have been widely used due to their excellent isolation performance, but the systems with high flexibility have the critical problem of large transient response by the impulsive force of the moving mass in operation of the equipment. In this paper, the hybrid vibration control system is proposed, which is combined the air springs with the semi-active MR dampers in order to satisfy the performances of isolation and vibration reduction simutaneously.

• The Journal of Korean Institute for Practical Engineering Education
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• v.1 no.1
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• pp.61-65
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• 2009

Due to the less variety of experiment equipments for engineering education, the development of designated educational equipment is really in urgent need at most time. Especially for the in-depth engineering major subject, vibration engineering, there are almost no related educational equipments in Korea. Accordingly, in order to simulate the vibration phenomena occurred in the actual field, the development of educational equipment for vibration engineering theory and experiment education is required. This paper introduces four development educational equipments developed in graduated research works, which are critical speed test educational equipment, balancing machine educational equipment, isolation educational equipment using eddy current and active vibration isolation educational equipment. Through using them in experiment lesson, the utilization and practicality of educational equipment are verified. The proposed improvement for future development and application of educational equipment is shown in addition.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.291-298
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• 2000

This paper describes a theoretical and experimental investigation into an active vibration isolation system in which four electromagnetic actuators are installed in parallel with each of four passive mounts placed between a piece of equipment and a vibrating base structure. Decentralised velocity feedback control is employed, where each actuator is operated independently by feeding back the absolute equipment velocity at the same location. Although one end of each actuator acts at the sensor positions on the equipment, the control system is not collocated because of the reactive forces acting on the flexible base structure, whose dynamics are strongly coupled with the mounted equipment. Isolation of low frequency vibration is considered where the equipment can be modelled as a rigid body and the mounts as lumped parameter springs and dampers. Control mechanisms are discussed, and some experimental and simulation results are reported.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.14 no.2
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• pp.88-95
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• 2018

In this study, to enhance the seismic performance of nuclear power plants (NPP), a small laminated rubber bearing (LRB) is chosen as a seismic design option of the vulnerable equipment. Prior to the application of equipment base isolation, it is necessary to review the feasibility that the technique contributes enough to the seismic performance of NPP by analysis. At first, some preliminary design of small LRBs for equipment is carried out. Design parameters such as horizontal and vertical stiffnesses, design natural frequencies are checked by calculation and analysis for the four design options considering various upper weights. Performance test of small LRB is to be carried out to verify static performance using the results.